Research

Genetic polymorphisms in monoamine neurotransmitter systems show only weak association with acute post-surgical pain in humans

Hyungsuk Kim^1,2 , Hyewon Lee^1,2 , Janet Rowan³ , Jaime Brahim⁴ and Raymond A Dionne^1,2

¹National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA

²Pain and Neurosensory Mechanisms Branch, National Institute of Dentaland Craniofacial Research, National Institutes of Health, Bethesda, MD, USA

³Department of Nursing, Magnuson Clinical Research Center, National Institutes of Health, Bethesda, MD, USA

⁴Clinical Research Core, National Institute of Dental and CraniofacialResearch, National Institutes of Health, Bethesda, MD, USA

author email corresponding author email

Molecular Pain 2006, 2:24doi:10.1186/1744-8069-2-24

Published:	18 July 2006

Abstract

Background

Candidate gene studies on the basis of biological hypotheses have been a practical approach to identify relevant genetic variation in complex traits. Based on previous reports and the roles in pain pathways, we have examined the effects of variations of loci in the genes of monoamine neurotransmitter systems including metabolizing enzymes, receptors and transporters on acute clinical pain responses in humans.

Results

Variations in the catecholamine metabolizing enzyme genes (MAOA and COMT) showed significant associations with the maximum post-operative pain rating while the serotonin transporter gene (SLC6A4) showed association with the onset time of post-operative pain. Analgesic onset time after medication was significantly associated with the norepinephrine transporter gene (SLC6A2). However, the association between COMT genetic variation and pain sensitivity in our study differ from previous studies with small sample sizes, population stratification and pain phenotype derived from combining different types of pain stimuli. Correcting for multiple comparisons did not sustain these genetic associations between monoamine neurotransmitter systems and pain sensitivity even in this large and homogeneous sample.

Conclusion

These results suggest that the previously reported associations between genetic polymorphisms in the monoamine neurotransmitter systems and the interindividual variability in pain responses cannot be replicated in a clinically relevant pain phenotype.